HP postcode district map, Hemel Hempstead
Supplier statuses last checked .
The HP postcode area covers 24 districts and 14,101 live postcodes, from HP1 to HP27. It is centred on High Wycombe and also covers Hemel Hempstead, Aylesbury, Wendover, Beaconsfield and Princes Risborough.
Districts here average 588 postcodes.
Where the HP districts sit
4 districts are plotted without a label where labels would overlap; every one is in the table below.
Where HP sits
It falls across Buckinghamshire and Hertfordshire.
Water supply across HP
All 24 HP districts are supplied by Affinity Water. That makes HP simple in a way many areas are not: one company, one set of rules, one status to check.
Affinity Water has a hosepipe ban in force from 11 July 2026, covering the whole of HP.
The shape of the HP area
HP2 is the largest district with 987 postcodes around Hemel Hempstead, and HP8 the smallest with 220. The area divides into 78 postcode sectors.
The numbering is not continuous. HP runs up to 27 but has only 24 districts, so 3 numbers are unused:.
Several districts share a settlement, which is a common source of confusion when a form rejects an address: HP11, HP12, HP13, HP14 and HP15 all point at High Wycombe, HP1, HP2 and HP3 all point at Hemel Hempstead and HP19, HP20 and HP21 all point at Aylesbury.
What borders HP
HP sits next to LU (Luton) to the north east, WD (Rickmansworth) to the east, SL (Slough) to the south, UB (Ashford) to the south east and HA (Bushey) to the south east.
Its neighbours run in 4 different directions, so HP is landlocked by other postcode areas on most sides.
HP districts, settlements and water supply
| District | Principal settlement | Water company | Hosepipe ban status |
|---|---|---|---|
| HP1 | Hemel Hempstead | Affinity Water / Thames Water | Ban in force |
| HP2 | Hemel Hempstead | Affinity Water / Thames Water | Ban in force |
| HP3 | Hemel Hempstead | Affinity Water / Thames Water | Ban in force |
| HP4 | Berkhamsted | Affinity Water / Thames Water | Ban in force |
| HP5 | Chesham | Affinity Water / Thames Water | Ban in force |
| HP6 | Amersham | Affinity Water / Thames Water | Ban in force |
| HP7 | Amersham | Affinity Water / Thames Water | Ban in force |
| HP8 | Chorleywood | Affinity Water / Thames Water | Ban in force |
| HP9 | Beaconsfield | Affinity Water / Thames Water | Ban in force |
| HP10 | Beaconsfield | Affinity Water / Thames Water | Ban in force |
| HP11 | High Wycombe | Affinity Water / Thames Water | Depends on your supplier |
| HP12 | High Wycombe | Affinity Water / Thames Water | Depends on your supplier |
| HP13 | High Wycombe | Affinity Water / Thames Water | Depends on your supplier |
| HP14 | High Wycombe | Affinity Water / Thames Water | Ban in force |
| HP15 | High Wycombe | Affinity Water / Thames Water | Ban in force |
| HP16 | Wendover | Affinity Water / Thames Water | Ban in force |
| HP17 | Princes Risborough | Affinity Water / Thames Water | Depends on your supplier |
| HP18 | Thame | Affinity Water / Thames Water | Depends on your supplier |
| HP19 | Aylesbury | Affinity Water / Thames Water | Depends on your supplier |
| HP20 | Aylesbury | Affinity Water / Thames Water | Depends on your supplier |
| HP21 | Aylesbury | Affinity Water / Thames Water | Depends on your supplier |
| HP22 | Wendover | Affinity Water / Thames Water | Depends on your supplier |
| HP23 | Tring | Affinity Water / Thames Water | Ban in force |
| HP27 | Princes Risborough | Affinity Water / Thames Water | Ban in force |
Principal settlement is the town or city each district sits in or nearest to, derived from OS Open Names. It is not the Royal Mail post town, which is licensed data and not published openly. Status is resolved live from each company’s own notice.
Water hardness in HP
No water company covering HP publishes hardness figures as open data. The gap is named per district below so you know who to ask.
| District | Hardness | As published | Supply zone | Published by |
|---|---|---|---|---|
| HP1 | Not published by Affinity Water. Check with your supplier. | |||
| HP2 | Not published by Affinity Water. Check with your supplier. | |||
| HP3 | Not published by Affinity Water. Check with your supplier. | |||
| HP4 | Not published by Affinity Water. Check with your supplier. | |||
| HP5 | Not published by Affinity Water. Check with your supplier. | |||
| HP6 | Not published by Affinity Water. Check with your supplier. | |||
| HP7 | Not published by Affinity Water. Check with your supplier. | |||
| HP8 | Not published by Affinity Water. Check with your supplier. | |||
| HP9 | Not published by Affinity Water. Check with your supplier. | |||
| HP10 | Not published by Affinity Water. Check with your supplier. | |||
| HP11 | Not published by Affinity Water. Check with your supplier. | |||
| HP12 | Not published by Affinity Water. Check with your supplier. | |||
| HP13 | Not published by Affinity Water. Check with your supplier. | |||
| HP14 | Not published by Affinity Water. Check with your supplier. | |||
| HP15 | Not published by Affinity Water. Check with your supplier. | |||
| HP16 | Not published by Affinity Water. Check with your supplier. | |||
| HP17 | Not published by Affinity Water. Check with your supplier. | |||
| HP18 | Not published by Affinity Water. Check with your supplier. | |||
| HP19 | Not published by Affinity Water. Check with your supplier. | |||
| HP20 | Not published by Affinity Water. Check with your supplier. | |||
| HP21 | Not published by Affinity Water. Check with your supplier. | |||
| HP22 | Not published by Affinity Water. Check with your supplier. | |||
| HP23 | Not published by Affinity Water. Check with your supplier. | |||
| HP27 | Not published by Affinity Water. Check with your supplier. | |||
Hardness is published per census area, not per postcode, so these figures characterise a district rather than measuring one address. They are a scale and taste matter, not a safety one. Hardness data version wessex-water@2022-2025+yorkshire-water@2026.
Download the HP data
No signup, no email wall. GeoJSON carries the district points, the supplier and the live status, so it can be dropped straight into a map.
District positions are averaged postcode centroids from OS Code-Point Open. They show roughly where a district sits, not where its boundary runs, and are not legal boundaries.
Frequently asked questions
How many postcode districts are in the HP area?
There are 24 HP postcode districts, running from HP1 to HP27, and they contain 14,101 live postcodes across 78 sectors.
What towns does the HP postcode area cover?
HP covers High Wycombe, Hemel Hempstead, Aylesbury, Wendover, Beaconsfield and Princes Risborough. The area takes its name from High Wycombe, and each district is listed with its settlement in the table on this page.
Which water company supplies HP postcodes?
Affinity Water supplies all 24 HP districts. Supply boundaries follow the pipe network rather than postcode geography, so confirm against your water bill if you are near the edge of the area.
Why do HP11 and HP12 both say High Wycombe?
HP11, HP12, HP13, HP14 and HP15 all serve High Wycombe, covering different parts of it. A single town routinely needs more than one postcode district once it passes a few thousand delivery points, so this is normal rather than an error in an address.
Can I download a free HP postcode map?
Yes. This page offers the HP districts as GeoJSON, CSV and SVG, free and with no signup or email address required. The GeoJSON carries each district's position, its water company and its current restriction status, so it can be dropped straight into a mapping tool.
Which councils cover the HP postcode area?
HP reaches into Buckinghamshire and Hertfordshire. A postcode area is not a council area: they were drawn for different purposes and a single district can sit across a council boundary, so your postcode does not tell you which authority you pay.
Why is there no HP26 postcode district?
HP26 is not in use. Postcode districts are allocated as sorting requirements change rather than numbered straight through, and a code that is retired or never brought into service is not reissued, so gaps in the sequence are normal.